- Palbociclib plus endocrine therapy (ET) with exemestane plus ovarian function suppression with gonadotropin-releasing hormone agonist (leuprolide) extends survival by 6 months relative to capecitabine chemotherapy alone in premenopausal hormone receptor (HR)-positive metastatic breast cancer (mBCa).
Why this matters
- Although clinical guidelines recommend endocrine therapy as the top treatment option, capecitabine is increasingly used in real-world patients with premenopausal or menopausal mBCa.
- Korean phase 2 multicenter randomized controlled trial (n=178) of palbociclib (125 mg/day for 21 days every 4 weeks)+exemestane (25 mg/day for 28 days)+leuprolide (3.75 mg subcutaneously every 4 weeks) vs capecitabine (1250 mg/m2 twice daily for 2 weeks every 3 weeks).
- Primary outcome was PFS.
- Funding: Pfizer; other industry sponsors.
- Median follow-up was 17 months (interquartile range, 9-22 months).
- Combination therapy group's median PFS was 20.1 months (95% CI, 14.2-21.8 months) vs 14.4 months (95% CI, 12.1-17.0 months) in the chemotherapy group (HR, 0.659; 95% CI, 0.437-0.994).
- Combination therapy had higher rates of treatment-related grade 3 or worse neutropenia (75% vs 16% in the chemo group), but lower rates of treatment-related serious adverse events (2% vs 17%, respectively).
- Open-label design.